Heat exchanger



Nov. 27, 1951 R. RUEMELIN I 2,576,309

HEAT EXCHANGER Filed Jan. 14, 1949 2 SHEETS-SHEET 1' Nov. 27, 1951 R. RUEMELIN HEAT EXCHANGER Y I Filed Jan. 14 1949 QSHEETS-SHEET 2 Patented Nov. 27, 1951 "UNl'lEE STATES iQA'lENT @EFFECE HEAT EXCHANGER Richard Ruemelin, Milwaukee, Wis.

Application January 14, 1949, Serial No. 70,970

. 2 Claims. 1.

This invention relates toimprovements in heat exchangers which are particularly well adapted for the drying and cooling of compressed air.

Compressed air is used in various industrial applications such as sand blasting; painting, pneumatic tool operation and the like,-and it is important that the compressed air so used be substantially free of moisture. To this. end dryers have been. heretofore'develope'd which sep-' arateexcess moisture from the air by means of an air cooling apparatus The dryers heretofore'developed have comprised intricate casings Whichare not only difficult and expensive to manufacture but, in addition, are difficult to disassemble and clean.

It is therefore a general object of the present invention to provide a heat exchanger adapted to utilize a fluid coolant. and having the heat transzontally extending corrugations which give the annular chambers between said members a zigzag cross-sectional shape whereby a medium may flow in the form of a ribbon to exchange heat byimpingement against the corrugations.

A further object of the invention is to provide aconstruction wherein, because of the corrugations, expansion and contraction of the heat transfer elements may take place without detrimental results.

A further object of the invention is to provide an apparatus of the class described wherein the smallest diameter portion'of each of the tubular heat transfer elements is at least slightly greater than the largest diameter portion of the next adjacentelement inwardly thereof, thereby facilitating assembly or disassembly' of the 'apparatus 'for cleaning, or repair.

compact, strong and durable, which; is; inexpencan 2 sive to manufacture, which is efiicient in operation, and which is otherwise well adapted for the purposes described.

With the above and other objects in view, the

invention consists of the improved heat exchanger, and all of its parts and combinations, as set forth in the claims, and all equivalents thereof.

In the drawings accompanying and forming a part of this specification, wherein are shown two embodiments of the invention, and wherein the same reference characters indicate the same parts in all of the views:

Fig. 1 is a fragmentary vertical sectional view of the preferred form of the invention;

Fig. 2 is a transverse sectional view taken along the line 22 of Fig. 1; and f Fig. 3 is a fragmentary vertical sectional view of a modified form of the invention.

Referring more particularly to Fig. 1 of the drawing, the numeral 5 indicates a cylindrical outer shell fixed at its upper end to a top ring 6, and fixed at its lower end to a similar bottom ring 1. The major portions of the top and. bottom rings 6 and I projectoutwardly from the shell 5 and form attaching flanges. Fixed tothe inner surfaces of the top and bottom rings 6 and l and spaced inwardly from the inner surface of the shell5 is a tubular heat transfer element 8 which is preferably concentric with the shell 5 and which is preferably formed with horizontal annular corrugations 9. Positioned concentric with the element 8 are tubular heat transfer elements l0, ll and I2. The heat transfer elements 10, i l and I2 are formed with annular horizontal corrugations which preferably correspond with the corrugations 9 of the element8, as shown in Fig. 1. At their upper ends the inner surface of theelement I0 and the outer surface of the element II are fixed to a head ring [3. Similarly associated with the lower ends of the elements l0 and II is a bottom head ring l4. Fixed to the inner surface vof the element [2 at its upper end is a circular headplate I5, and similarly associated with the lower end of the element i2 is a circular bottom plate 5.

Fixed. to the upper surface of the upper ring 6, as by bolts and nuts H, is an upper head [8 having the shape of an inverted bowl and being formed with an attaching flange IS. The head I8 is also formed with an air inlet connection into which is adapted to be threaded an air supply conduit 20. Projecting vertically through a central portion of the head I8 and through the circular plate 15 is a conduit 2|. The conduit 2| may have a threaded connection with the plate I5, and the head I8 is preferably provided with a stuffing box 22 and gland 23 sealingly surrounding the conduit 2| as shown. A tubular spacer 24 may be positioned around the conduit 2| to extend between the plate l and the stuffing box 22.

A conduit 25 extends vertically through the head l8 and through the head ring [3 as shown. The conduit 25 is associated with the headring l3 and with the head I8 in substantially the same manner as the conduit 2| is associated with the plate l5 and the head |8, having associated therewith a stuifing box 26, a gland 27, and a tubular spacer 28. The interior of the head |8- is also formed with a boss 29 which is tapped to receive a vertically depending stud 30. Surrounding the stud 30 and extending between the boss 29 and the upper surface of the ring I3 is a tubular spacer 3|.

Attached, as by boltinggto the lower surface of the lower ring I is a lower head 32. The head 32 is substantially bowl-shaped and is formed at its upper margin with an outwardly extending annular attaching flange 33. The head 32 is also formed with an air outlet connection 34 into which is adapted to be threaded an air discharge conduit 35. Positioned substantially concentrically within the head 32, and spaced from the bottom end thereof and from the plate I6, is an inverted bowl member 36 having substantially vertically extending side walls. A horizontally extending conduit 31 within the head 32 is supported at one end in the outlet connection 34 as shown in Fig. l. The conduit 3'! extends through a side wall portion of the bowl member 36, as at 38, and has an inner end wall 39. The upper portions of the inner end of the conduit 31 are cut away as at 49.

Extending upwardly through the lower head 32, conduit 31, bowl member 36, and plate I6, is a conduit 4|. The head 32 is provided with a stuffing box 42 and with a gland 43 sealingly surrounding the conduit 4|. A tubular spacer 44 surrounds said conduit and extends from the stuffing box 42 to the lower surface of the plate I6 Extending vertically through the head 32, bowl member 36, and ring I4, is a conduit 45. The head 32 is provided with a stufling box 46 and with a gland 4'| sealingly surrounding the conduit 45, and a tubular spacer 48 surrounds theconduit and extends between the stuffing box 46 and the lower surface of the annular plate I. The conduits 4| and 45 may respectively have a threaded connection with the plates l6 and M. The lower'head 32 is formed with a drain opening 49 which may be closed with a plug 58. The head 32 may also be formed with a boss 5| which is tapped to receive an upstanding stud 52. A tubular spacer 53 may surround the stud 52 and extend between the boss 5| and the annular plate M, as shown.

Threaded into a lower side wall portion of the casing 5 is a conduit 54, and threaded into an upper side wall portion of said casing is a preferably diametrically oppositely positioned conduit 55.- An inlet connection 56 leads from a suitable source of cold Water under pressure. Through suitable branch connections the inlet 56 communicates with shutofi valves 51, 58 and 59. As shown in Fig. 1, the valve 51 communicates with the conduit 54, the valve 58 communicateswith the conduit 45, and the valve 59 communicates with the conduit 4|. The conduits 2|, 25 and 55 may communicate with a common discharge conduit (not shown).

- It will be noted from the drawing that the size of the heat transfer elements 8, IO, N and I2, and the corrugations therein are such that the smallest diameter portion of any one of said elements is slightly larger than the largest outer diameter portion of the next inwardly adjacent element. The corrugations in the heat transfer elements and the spacing between said elements provide annular chambers 69, 6| and 62 having serpentine vertical cross-sectional shapes and having substantially the same thickness. In addition to the chambers 60, BI and 62, there is an annular chamber 63 between the casing 5 and the element 8, and there is a central chamber 64 Within the element |2 and the end plates l5 and I6.

In operation, cold water under pressure enters the inlet connection 56, and the valves 5?, 58 and 59 being normally open, said water flows into and fills the chambers 63, 6| and 64. Hot compressed air enters the upper head I8 through the conduit 28 and connection l9, and passes down through the annular chambers 68 and 62, where it is cooled by the cold water flowing upwardly through the chambers 63, 6| and 64. Simultaneously with the cooling of the air, the cold water is heated by the air. The heated water flows out of the conduits 2 25 and 55. As the air is cooled during its passage through the chambers 69 and 62, its saturation point is correspondingly reduced, with the result that moisture is condensed from the air. This moisture is deposited on the heat transfer elements and flows down the inner surfaces of the chambers 60 and 62 and collects in the bottom of the lower head 32 from which it may be periodically drained by the removal of the plug 58. If desired, the drain hole 49 may communicate with a drain pipe and with a drain trap in the manner disclosed in Fig. 1 of my Patent No. 1,899,988. Upon leaving the chambers 68 and 62 the cooled air travels downwardly around the bowl member 36 and then flows upwardly within said bowl and out through the conduits 31 and 35, entering said conduits via the cutaway portion 48. The inverted bowl member 36 and the conduit 31 combine to form a trap or bafile system which prevents any entrained moisture within the lower head 32 from passing out of the conduit 35. If desired a separate trap inserted in a portion of the line 35 may be used instead of a trap within the apparatus. I

The improved air drier is very easily disassembled and reassembled. To disassemble the apparatus, all that is necessary is to disconnect the conduits 2|, 25, 4| and 45 from the water inlet and discharge systems and to loosen the glands 23, 21, 43 and 41. The head l8 may then be unbolted and lifted off the casing 5 and off of the conduits 2| and 25. With the head l8 off, the unit composed of the conduit 2 element |2, end plates l5 and I6, and conduit 4|, may be lifted out. As this is done, the conduit 4| slides through the gland 43. Due to the fact that, the smallest inner diameter portion of each of the elements is larger than the largest outer diameter portion of the element next inwardly adjacent, the element |2 can pass freely upwardly through the element Upon removal of the abovementioned unit, a second unit consisting of the upper and lower rings l3 and I4, elements It] and H, and conduit 45, can be lifted out in the same manner and for the same reasons as the first unit. Removal of the abovementioned units not only facilitates cleaning or repair thereof, but also affords complete access to the interior of the remainder of the apparatus for any purpose.- When desired, the

lower head 32 may-be easily and quickly removed by 'unbolting it from thelower plate 1-.

Fig. 3- showsamodified form of the invention and is of the double pass type. The parts of the modified. form of the invention which are analo guns to like parts in thepreferred form of the invention are designatedby the samereference characters primed. In the modified form of the invention there .is an outer cylindrical shell or casing 5? having an open upper end and having its bottom end closed as shown. There is an end ring 6' fixed to the upper end of the shell 5, and fixed to the end ring 6 is, an upperhead 1-8 which is. formed with an air inlet connection l9. Positioned within and, concentric with the casing 5,, and having its upper end fixed tothe inner surfaceof the end ring 6;- is a heat transfer element 8' which has its. lower end closed by a bottom wall, as shown. Projecting upwardly from a central portion ofthe bottom wall of the element 8', and opening through said wall, is a conduit 65.

Positioned concentrically within the tubular heat transfer element 8, and preferably in subinner surface'of'the upper endof the element IQ,

and the outer surface of the upper end of the element H. A ring 66 issealingly connected to the inner surface of the upper. end of the element H, and sealingly connected to the inner surface of the ring 66 is an upwardly projecting air outlet out the conduit 55. Hot compressed air which enters the apparatus through the .air inlet conduit 20 and 'throughthe: connection l9" flows into the head 18. The air then flows downwardly through the chamber 60-; and, upon passing out of the bottom end. of; the chamber'fi 5, said air flows inward-1 y and upwardly, as indicated by the arrows, into the lower .end of the chamber 52 The air, upon flowing, out of the upper end of the chamber 62, enterssthe air outletconduit 6.1 through which it leaves the apparatus.

As in the preferred form of the invention, the cooling effect of the water causes moisture to be condensed from the air flowing through the apparatus. This moisture will flow downwardly and will collect on the inner surface of the bot tom wall of'the element 8', from whichitmay be drained through condensate. drain conduit 12..

The drain conduit M provides means for empty-'- ing the chambers ii I and fi i'when necessary.

vAsis alsotrue in the-preferred form of the invention, the smallest inner diameter portion of each of the tubular heat transfer elements of the modified form is slightly larger. than the largest outer diameter. portion of the tubular heat transfer next adjacentzelement inwardly. thereof. It. is apparent, therefore, that during assembly or disassembly of the modified form :of the apparatus, the, heat transfer elements thereof 'may bereadily placed in position within or removed fromone another as. desired. The improved apparatus is relatively inexpensive to manufacture because. of the, fact that sheet metal is employed in the heat transfer elements rather than expensive castings which have been common heretofore. The improved apparatus is efficient in operation and is particularly easy to disassemble and clean,,the latter feature materially reducing conduit 6 7 which extends through the head 18.

The head [8' is provided with a suitable .stufling box 68 and with a gland 69 sealingly surrounding the air outlet conduit 61.

Extending downwardly through the head I8 and through the ring 13, and communicating withthe annular chamberifil is a cold water inlet conduit H3. Threaded into the casing 5 and communicating with the chamber 63 is a water outlet conduit 55'. Communicating between the lower end of the chambers 6| and 64' is a conduit 1 I. Extending upwardly through the bottom wall of the casing 5' and opening through the bottom wall of the element 8 is a condensate drain pipe 12 which may have its lower end closed with a cap 73. Extending upwardly through the bottom wall of the casing 5', through the bottom wall of the element 8 and through the circular plate I6 is a drain pipe 14 which may have its bottom end closed with a cap 15. The bottom wall of the casing 5' may be provided with suitable stufiing boxes 16 and with glands 11 sealingly surrounding the pipes 12 and 14.

In operation, cold water enters the apparatus through the conduit 10 and flows downwardly into and through the annular chamber BI. This water flows from the bottom of the chamber 6| through the conduit H and into the chamber 64, through which it then flows upwardly to enter the upper end of the conduit 65. The water then flows downwardly through the conduit 65 and enters that portion of the chamber 63 between the bottom walls of the casing 5 and the element 8'. The water then fiows outwardly and upwardly in the chamber 63 and passes the cost of maintenance of the improved apparatus. V

Due to the corrugations, heat exchange takes place very efliciently ,because of impingement against the corrugations of the medium flowing in the exchanger.

.It is obvious that the, apparatus is suitable. for use with any gases. or liquids, and is suitable for a variety of uses such as in an air dryer, still or water heater, a

Various changes and modifications may be made without departing from the spirit of the invention, and all of such changes are contemplated, as may come within the scope of the claims.

What I claim is:

1. In an air drier, a substantially cylindrical outer shell having an open upper end and a closed lower end, a first tubular heat transfer element within said casing having a closed lower end and having an open upper end, the upper margins of said element and said casing being sealingly connected, said element having its side and end walls spaced from and adjacent the side and end walls of the casing to form a cup-shaped first fluid chamber therebetween; a second tubular heat transfer element spaced concentrically within said first element and having open ends; a third tubular heat transfer element spaced concentrically within said second element and having open ends, said second and third elements being sealingly connected at their upper and lower margins to form a second fluid chamber therebetween; a fourth tubular heat transfer element spaced concentrically within said third element and having its upper and lower ends closed to form a third fluid chamber therein, there being a first annular air chamber between said first and second elements and a second annular airrchamber between said third and fourth elements; a head for closing the upper end of said casing; an air inlet communicating with the .upper end of said first air chamber, said first and second air chambers having communication at their lower ends; an air outlet leading from the upper end of said third element and communicating with the upper end of said second air chamber; a fluid connection between the lower ends of said second and third fluid chambers; a conduit projecting upwardly from the end wall of said first element and through the lower end of said third fluid chamber to adjacent the upper end thereof to provide communication between said first and third fluid chambers; a fluid inlet communicating with the upper end of said second fluid chamber; and a fluid outlet communicating with the upper end of said first chamber, said tubular heat transfer elements having sidewall portions formed with corrugations which impart to said air chambers and said second fluid chamber a serpentine shape in vertical section, and said elements being of such diametrical dimensions that each may be removed from the adjacent elements by coaxial relative movement.

2. In an air drier, a substantially cylindrical outer shell having an open upper end and a closed lower end, a first tubular heat transfer element within said casing having an open upper end, the margins of which are sealed to the upper margins of said casing, and having a closed lower end, said element having its side wall and end wall spaced from and adjacent the side and end walls of the casing to form a cup-shaped first fluid chamber therebetween; a second tubular heat transfer element spaced concentrically within said first element and having open ends 5 a third tubular heat transfer element spaced concentrically within said second element and having open ends, said second and third elements being joined at their upper and lower margins to form a second fluid chamber therebetween; a fourth tubular heat transfer element spaced concentrically within said third element and having its upper and lower ends closed to form a third fluid chamber therein, there being a first annular air chamberbetween said first and second elements and a second annular air chamber between said third and fourth elements; a head for closing the upper end of said casing; an air inlet in said upper head .andcommunieating with the upper end of said first airchamher, said first and second air chambers having communication at their lower ends; an air outlet projecting through said upper head and connected to the upper end of said third element and communicating withthe upper end of said second air chamber; a fluid connection between the lower ends of said second and third fluid chambers; a conduit projecting upwardly from the end wall of said first element and through the lower end of said third fluid chamber to adjacent the upper end thereof to provide communication between saidfirst and third fluid chambers; a fluid inlet communicating with the upper end of said second fluid chamber; and a fluid outlet communicating with the upper end of said first chamber, said tubular heat transfer elements having sidewall portions formed with corrugations which impart to said air chambers and said second fluid chamber a serpentine shape in vertical section, and said elements being of such diametrical dimensions that each may be removed from the adjacent elements by coaxial relative movement.

RICHARD RU'EMELIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Feb. 10, 1921 

